Facebook is wonderful because it allows me to keep in touch with my family and friends all over the world and brings that closeness despite the distance and our busy life. But we have to know what information we would rather keep private and what we don't mind sharing. I have seen people making stupid comments, post silly pictures that could backfire and affect their jobs etc. The usage of FB are fantastic. But if you use it wrongly or for the wrong reason then blame yourself.
If you are worried about privacy, adjust your settings so that nobody but your friends can see your stuff. If you are still worried, all you have to do is not to post embarrassing photos and to avoid saying anything stupid or defamatory. Remember, it is not compulsory for you to use all of the features of Facebook. Only use it for what you want to use it for.
I personally find it very nice for posting family pictures because most of my family are on the other side of the world from me. But I see no point in telling everyone every time I go to the toilet. What's the point in doing that?